Nano-coating protection method for electrical connectors

ABSTRACT

Introduced here is a plasma polymerization apparatus and process. Example embodiments include a vacuum chamber in a substantially symmetrical shape to a central axis. A rotation rack may be operable to rotate about the central axis of the vacuum chamber. Additionally, reactive species discharge mechanisms positioned around a perimeter of the vacuum chamber in a substantially symmetrical manner from the outer perimeter of the vacuum chamber may be configured to disperse reactive species into the vacuum chamber. The reactive species may form a polymeric multi-layer coating on surfaces of the one or more devices. Each layer may have a different composition of atoms to enhance the water resistance, corrosion resistance, and fiction resistance of the polymeric multi-layer coating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/404,575, filed May 6, 2019, which claims priority to U.S. ProvisionalPatent Application Ser. No. 62/667,408 filed on May 4, 2018 and U.S.Provisional Patent Application Ser. No. 62/667,413 filed on May 4, 2018.The contents of the above-identified applications are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to plasma polymerization technologiesand, more specifically, to a plasma polymerization coating apparatus andprocess.

TECHNICAL BACKGROUND

The plasma polymerization coating treatment is an important surfacetreatment technique because of its advantages over other conventionaltechniques. For example, in plasma polymerization coating, polymers canbe directly attached to a desired surface where molecular chains grow.This reduces the overall number of steps necessary for coating thesurface to be treated. Other advantages include the availability of awider selection of monomers, as compared to conventional chemicalpolymerization techniques.

However, due to various shortcomings in existing designs of conventionalplasma coating equipment, conventional plasma polymerization treatmentoften suffers from production limitations, resulting in small batchsize, low efficiency, high cost, and poor batch uniformity.

BRIEF DESCRIPTION OF DRAWINGS

One or more embodiments of the present disclosure are illustrated by wayof example and not limitation in the figures of the accompanyingdrawings, in which like references indicate similar elements. Thesedrawings are not necessarily drawn to scale.

FIG. 1 is a schematic front sectional view of the structure of anexample plasma polymerization coating apparatus with planetary rotationaxles arranged on the rotation rack, according to one or moreembodiments of the present disclosure.

FIG. 2 is a schematic top view of the structure of the example apparatusshown in FIG. 1, according to one or more embodiments of the presentdisclosure.

FIG. 3 is a flow diagram that illustrates an example process for plasmapolymerization.

FIG. 4 is a block diagram illustrating an example of a processing systemin which at least some operations described herein can be implemented.

FIG. 5 is a schematic front sectional view of the example plasmapolymerization coating apparatus with optional shafts and gears forrotating rotation racks and planetary rotation shafts, according to oneor more embodiments of the present disclosure.

FIG. 6 is a flow diagram that illustrates another example process forplasma polymerization, according to one or more embodiments of thepresent disclosure.

FIG. 7 is a diagram that illustrates an example plasma polymerizationcoating applied on a device, according to one or more embodiments of thepresent disclosure.

DETAILED DESCRIPTION

Certain embodiments of the present disclosure will be described indetail below in reference to the related technical solutions andaccompanying drawings. In the following description, specific detailsare set forth to provide a thorough understanding of the presentlydisclosed technology. In other embodiments, the techniques describedhere can be practiced without these specific details. In otherinstances, well-known features, such as specific fabrication techniques,are not described in detail in order to avoid unnecessarily obscuringthe present technology. References in this description to “anembodiment,” “one embodiment,” or the like mean that a particularfeature, structure, material, or characteristic being described isincluded in at least one embodiment of the present disclosure. Thus, theinstances of such phrases in this specification do not necessarily allrefer to the same embodiment. On the other hand, such references are notnecessarily mutually exclusive. Furthermore, the particular features,structures, materials, or characteristics can be combined in anysuitable manner in one or more embodiments. Also, it is to be understoodthat the various embodiments shown in the figures are merelyillustrative representations and are not necessarily drawn to scale.

As previously mentioned, plasma polymerization coating is capable ofproducing results with highly desirable characteristics and can performwell in certain applications, such as hydrophobic film coating. However,since the polymer coating tends to be very thin, it can be difficult toachieve the desired uniformity of the coating.

To perform plasma polymerization coating, a device to be treated can befirst placed in a vacuum chamber, and then carrier gas and gaseousorganic monomer are dispersed into the vacuum chamber. The gaseousorganic monomer is turned into a plasma state by discharging electricalpower to the monomer to produce various types of reactive species. Next,additional reactions between the reactive species and the monomer, orbetween the reactive species themselves, take place and form a polymerfilm on the device's surface. At various points in the plasmapolymerization coating process, the atmosphere of the vacuum chamber mayinclude one or more of: carrier gas, gaseous organic monomer, plasmaresulting from discharging electrical power to the monomer, reactivespecies resulting from the combination of plasma and monomer vapor, etc.In certain applications such as hydrophobic or oleophobic film coating,plasma polymerization coating is capable of producing results withhighly desirable characteristics.

Conventional plasma coating devices are typically equipped with arectangular vacuum chamber, and as a result, during the coating process,the positions of the device-carrying platforms and the device placedthereon are typically fixed within the conventional vacuum chamber.Because different devices in the same batch are in different positionsin the vacuum chamber, they are at varying distances from theelectrodes, monomer/carrier gas outlet, vacuum gas outlet, etc.Accordingly, it is inevitable that the thickness of the coats applied toeach device vary based on the different locations of each device withinthe chamber. Hence, in order to reduce the variation in uniformitywithin the same batch, currently available plasma coating devicestypically adopt a vacuum chamber with a small volume and are treated insmall-quantity batches. This process greatly reduces processingefficiency and increases the cost. Even so, it may fail to produce asatisfactory batch uniformity that meets a client's requirement. Withthe rapid expansion of polymer coating applications, demands for suchprocessing are increasing rapidly.

Accordingly, disclosed here are plasma coating apparatus and techniquesthat address the technical problems in the existing plasma coatingprocesses, such as small batch size, low efficiency, high cost, and poorbatch uniformity. In some embodiments, the uniformity of the appliedplasma polymerization coating is enhanced using control mechanisms suchas controlling the evacuation of gases from a vacuum chamber.

Plasma chemical vapor deposition (PCVD) is a technology that uses plasmato produce a protective coating on the surface of a device. The PCVDprocess activates a reaction gas and promotes chemical reactions on thesurface or proximity of a device to produce a protective coating.

PCVD is a process that offers numerous advantages during the productionof a protective coating. For example, PCVD is a dry process that doesnot damage the device receiving the coating. When compared with aparylene vapor deposition method, the PCVD technology has a lowerdeposition temperature to avoid damage to the device receiving thecoating while offering greater control of the monomers used and thecoating structure formed. Additionally, the coating can be appliedevenly on non-uniform or irregularly shaped devices.

Additionally, the coating processing can be conducted on gold fingersand other conducting members of a device because the coating does notaffect a product's normal functions such as current conduction, heatdissipation, and data transmission. Therefore, a masking operation isnot necessary to control which areas of a device will receive the plasmapolymerization coating. Therefore, the simplified coating process canimprove production throughput and higher production yields. Finally,PCVD technology is more environmentally friendly than applying athree-coating protection layer using liquid chemicals because of thereduced number of undesired byproducts.

In addition to the advantages during production, PCVD produces aprotective coating that has significant advantages over coatingsproduced using other methods. For example, relative to conventionalwater resistance protection through a mechanical structure (e.g., gluecoating, rubber rings, and gaskets), the protection provided by theplasma polymer film avoids complex mechanical designs, high cost, lowproduction yield, and susceptibility to deterioration from wear andtear. Additionally, by avoiding mechanical structures to provide waterresistance, the PCVD protective coating improves the appearance of theproduct and improves user experience.

Another advantage of the coating is the strong bonding force to thedevice that allows the coating to remain on the surface of the devicewhile sustaining normal wear and tear. The coating also has stablechemical and physical properties that provides resistance to damage fromsolvents, chemical corrosion, heat, and abrasion. Additionally, the PCVDprocess is capable of generating coatings that are that can be as thinas a few nanometers. Therefore, relative to other coatings, the plasmapolymer film provides an effective method for providing a waterresistant and corrosion resistant coating that is thin and durable. Inthe following description, numerous specific details are set forth suchas examples of specific components, circuits, and processes to provide athorough understanding of the present disclosure. Also, in the followingdescription and for purposes of explanation, specific nomenclature isset forth to provide a thorough understanding of the presentembodiments. However, it will be apparent to one skilled in the art thatthese specific details may not be required to practice the presentembodiments. In other instances, well-known circuits and devices areshown in block diagram form to avoid obscuring the present disclosure.

The term “coupled” as used herein means connected directly to orconnected through one or more intervening components or circuits. Any ofthe signals provided over various buses described herein may betime-multiplexed with other signals and provided over one or more commonbuses. Additionally, the interconnection between circuit elements orsoftware blocks may be shown as buses or as single signal lines. Each ofthe buses may alternatively be a single signal line, and each of thesingle signal lines may alternatively be buses, and a single line or busmight represent any one or more of a myriad of physical or logicalmechanisms for communication (e.g., a network) between components. Thepresent embodiments are not to be construed as limited to specificexamples described herein but rather to include within their scope allembodiments defined by the appended claims.

Plasma Polymerization Coating Apparatus

Shown in FIGS. 1 and 2 is a plasma polymerization coating apparatus 100according to one or more embodiments of the present disclosure forapplying a plasma polymerization coating to device 115. In an exampleembodiment, the plasma polymerization coating apparatus includes vacuumchamber 101, porous electrode 102, radio frequency power source 103,discharge cavity 104, metal grid 105, pulse power source 106, dischargesource 107, discharge power source 108, carrier gas pipe 109, monomervapor pipe 110, tail gas collecting tube 111, rotation rack 112,planetary rotation shafts 113, planetary rotation platforms 114, device115 to be treated, vacuum pump 116, controller 117, rotary motor 118,and guide sleeve 119.

In some embodiments, device 115 may be a connector for transmittingelectrical signals. The connector may be an interface used to connecttwo or more devices and allow electrical signals to be transmittedbetween the connected devices. In some embodiments, the connector may bea USB™ connector (for example, Micro USB™, USB-A™, USB™ Type-Cconnector, micro-USB™ connector, etc.), an Apple™ Lighting connector, aHDMI™ connector, a flexible printed circuit (FPC) connector, aboard-to-board (BTB) connector, a probe connector, or a radio frequency(RF) coaxial connector. In other embodiments, device 115 may be ahousehold appliance, a mobile device, a computing device, a displaydevice, or a wearable device. In some examples, device 115 is a cellphone, headphone, wireless headphone, tablet computer, child watch,positioning tracker, laptop computer, audio system, unmanned aerialvehicle, augmented reality (AR) glasses, or virtual reality (VR)glasses.

Device 115 may gain improved durability and performance by undergoing aplasma polymerization processing. Durability and resilience to wear andtear is important because the device 115 may encounter frequent plug andunplug events and operate in harsh environments that increase thelikelihood of moisture and corrosion damage. Therefore, as will bedescribed in detail below, a plasma polymerization coating providesprotection against the various wear and tear encountered by device 115.For example, a plasma polymerization coating may provide a layer ofprotection that makes device 115 resistant to water and moisture (e.g.,condensation due to changes in temperature). Additionally, the plasmapolymerization coating may provide protection against acidic solvents,acidic atmospheres, and basic solvents. Finally, the plasmapolymerization coating may also provide protection or resistance againstsweat, cosmetics, and frequent changes of temperatures.

Vacuum Chamber

Vacuum chamber 101 functions as a container where polymerized plasma maybe applied to device 115. For purposes of the present disclosure, theterm “vacuum chamber” means a chamber having a lower gas pressure thanwhat is outside of the chamber (e.g., as a result of having vacuum pump116 pumping gas out of the chamber). The term does not necessarily meanthat the chamber is exhausted to a vacuum state. For the purposes ofdiscussion herein, vacuum chamber 101 may also be referred to as a“reaction chamber.” Vacuum chamber 101 may be a chamber where one ormore chemical reactions described herein (e.g., for implementing thedisclosed plasma coating techniques) take place. In some examples,during the coating process, vacuum chamber 101 can be first exhausted ofgas to a base pressure around 5 mTorr and then filled with carrier gas.After filling vacuum chamber 101 with carrier gas, the air pressure inthe vacuum chamber 101 may rise to around tens of mTorr. The volume ofvacuum chamber 101 may vary depending on the application, for example,between 50-3000 liters. Examples of the chamber material may includealuminum alloy or stainless steel.

Vacuum chamber 101 has a chamber body inner wall along the perimeter ofvacuum chamber 101. The inner wall of vacuum chamber 101 may becharacterized by a circular top view cross section with the samediameter as other top view cross sections, or a polygon with the sameedge length as other top view cross sections. Some embodiments of saidpolygon have at least six edges.

The top cover and the bottom cover of vacuum chamber 101 may be a flatplate or an arched structure, such as a spherical segment, a regularpolygon, or an oval. In some embodiments, the structure matches the topview cross section of the chamber body inner wall of vacuum chamber 101.

Porous Electrode

In some embodiments, porous electrode 102 can generate plasma forpre-treating the surface of the device 115 to be coated bypolymerization in subsequent steps. In particular, high electricitypower (e.g., over 600 watts) are continuously discharged through porouselectrode 102 to produce a strong plasma. The resulting plasma can beused for at least two purposes: (1) cleaning organic impurities on thesubstrate surface, such as water and oil stains, as well as (2)activating organic substrate to form dangling bonds to facilitatecoating deposition and enhance the binding force between the substrateand the coating. In some embodiments, this surface plasma pre-treatmentvia porous electrode 102 is optional.

In some embodiments, the porous electrode 102 may form a cylindricalshape or at least divided into two sections of cylindrical shape, andthe porous electrode 102 can be coaxial with the vacuum chamber 101. Theporous electrode 102 can be covered by holes, and the size of a hole canrange between 2 to 30 mm in diameter. The space between each hole canrange from 2 to 30 mm. Additionally, the holes may be arranged in auniform manner or with varying distances between each hole.

Porous electrode 102 is installed in vacuum chamber 101 near or proximalto the inner wall of vacuum chamber 101. Porous electrode 102 may form aporous arched structure within a distance from the inner wall of vacuumchamber 101. In some embodiments, the distance from porous electrode 102to the inner wall of vacuum chamber 101 can range between 1 to 6 cm.

Vacuum chamber 101 of the plasma polymerization coating apparatus 100may include a radio frequency power source 103 coupled to porouselectrode 102. In some embodiments, the radio frequency power source 103is configured to provide an electrical charge to the porous electrode102 to produce a treatment plasma to remove impurities from the surfaceof the one or more substrates. The radio frequency power source 103 canbe coupled to controller 117 to receive a radio frequency control signalthat controls the power output to the porous electrode 102.

For example, porous electrode 102 may be connected to a radio frequency(e.g., high frequency) power source 103. When power from radio frequencypower source 103 is applied to porous electrode 102, plasma is generatedfor removing impurities from the surface of device 115. The power ofradio frequency power source 103 may be configured to be between 15-1500watts. Note that, in some embodiments, the plasma generated during powerdischarge can be used for substrate surface cleaning and pre-treatment.According to some embodiments, the gas that is used to produce plasmafor cleaning (e.g., pre-treating the surface of the substrate) containsoxygen.

As mentioned above, radio frequency power source 103 is applied toporous electrode 102 to generate a plasma for removing impurities fromthe surface of device 115. In one or more embodiments, radio frequencypower source 103 is used for driving the electrical discharge even whenand if porous electrode 102 is covered by dielectric coatings. Incomparison, direct current (DC) power sources or low frequency powersources (e.g., under 50 Hz) do not have this advantage. The applicablehigh frequency applied by radio frequency power source 103 may rangefrom tens of kHz to several GHz. Typical high frequencies include 40kHz, 13.56 MHz, and 2.45 GHz, etc. The choice of the frequency maydepend on the technical requirement or specification, the existingproducts' material characteristics, and cost. It is noted that a personhaving ordinary skill in the art of dielectric coating should be able toselect a suitably high frequency to perform the coating of a specificmaterial.

Additionally, because electrodes of radio frequency power source 103alternates in polarity, the electrodes are identified as the drivingelectrodes and the grounding electrodes instead of the cathode and anodeelectrodes. In one or more embodiments of the disclosed apparatus,porous electrode 102, which connects to the output of the radiofrequency power source 103, is the driving electrode. In at least someof these embodiments, the wall of vacuum chamber 101 can act as thegrounding electrode. Additionally, or alternatively, tail gas collectingtube 111 can also act as the grounding electrode.

Discharge Cavity

Vacuum chamber 101 of the plasma polymerization coating apparatus 100includes a dispersal mechanism positioned around a perimeter of vacuumchamber 101. In some embodiments, vacuum chamber 101 is configured todisperse reactive species into vacuum chamber 101 in a substantiallyuniform manner. The dispersal mechanism can be configured to dispersereactive species toward the central axis of vacuum chamber 101, suchthat the reactive species form a polymeric coating on surfaces of theone or more substrates. The dispersal mechanism may include a dischargecavity 104 and a metal grid 105 configured to create a pressuredifferential between the discharge cavity and vacuum chamber 101. Themetal grid 105 may also be configured to reduce or prevent gas backflowfrom vacuum chamber 101 to the discharge cavity.

In some embodiments, discharge cavity 104 is connected to vacuum chamber101. Discharge cavity 104 includes discharge source 107 coupled to adischarge power source 108 to produce plasma for polymerization. One endof discharge source 107 can be connected to a discharge power source108. The other end of the carrier gas pipe 109 may be adjacent to acarrier gas source. Monomer vapor pipe 110 can be coupled to vacuumchamber 101, and an outlet thereof can be located in front of dischargecavity 104. The other end of monomer vapor pipe 110 can be connected toa monomer vapor source.

In some embodiments, discharge cavity 104 may form a cylindrical shape,and can be made from materials including, for example, aluminum, carbonsteel, or stainless-steel material. The diameter of discharge cavity 104can range from 5 to 20 cm, the depth from 3 to 15 cm, and the distancebetween two neighboring discharge cavities from 7 to 40 cm. The axes ofdischarge cavity 104 may be orthogonal to the axis of the vacuum chamber101 to provide the largest opening area to the plasma to travel to thevacuum chamber 101. In alternate embodiments, under the pressure ofseveral Pascal in the process, free diffusion dominates the plasmapropagation, so the orientation of the discharge cavity has littleimportance.

Various size ratios between the discharge cavity and the vacuum chamber.For example, a single, relatively large discharge cavity 104 allows fordispersal of a greater volume of carrier gas-based plasma. However, asingle discharge cavity provides for carrier gas-based plasma from asingle direction into the vacuum chamber 101 and thus does not provideadequate uniformity of the polymerization coating. Conversely, thenumber and distribution of the discharge cavities is determined by thedesired coating uniformity. Smaller discharge cavities 104 that areuniformly distributed provide greater uniformity of the applied coating.However, too many small discharge cavities present technical limitationsand increased costs. The final design should be optimized to provide abalance of uniformity, technical limitations, and cost.

Discharge cavity 104 is provided with carrier gas pipe 109 thatintroduces carrier gas from a carrier gas source to discharge cavity104. The carrier gas gets ionized in discharge cavity 104 and becomesplasma (i.e., a mixture of positive ions and electrons produced byionization). The carrier gas transfers energy to the monomer vapor toactivate the monomer vapor to a high-energy state (i.e., the monomervapor become activated species). In some embodiments, the carrier gasmay even cause some chemical bonds of the monomer to break and formreactive particles such as free radicals.

When the carrier gas encounters an electrical discharge from dischargepower source 108 at discharge source 107, the carrier gas forms aplasma. During the coating process, discharge cavity 104 discharge at arelatively low power to generate weak plasma. The weak plasma isintermittently released into vacuum chamber 101 by metal grid 105 toinitiate monomer polymerization and deposition on the surface of thesubstrate to form a polymerization coating. Depending on the embodiment,discharge source 107 may be a lamp filament, an electrode, an inductioncoil, or a microwave antenna. Discharge source 107 can have dischargepower ranging from 2 to 500 W.

Depending on the embodiment, the porous electrode 102 and dischargecavity 104 are independent of each other, and they can be operatedeither together or separately. In some embodiments, during the plasmapolymerization coating process, the porous electrode 102 is used for (1)pre-treatment of the samples and (2) post-cleaning of the chamber. Thatis to say, in these embodiments, the porous electrode 102 do not operateduring coating process. On the other hand, according to one or moreembodiments, discharge cavity 104 is mainly used for coating.Additionally, or alternatively, discharge cavity 104 can also be usedfor post-cleaning of the cavities themselves.

For purposes of the disclosure here, the term “strong plasma” isassociated with the higher power applied by radio frequency power source103 relative to the power applied by discharge power source 108. Thetypical discharge power for strong plasma can be several hundred watts,and the plasma density is between 10⁹-10¹⁰/cm³. Conversely, the term“weak plasma” is associated with the lower power applied by dischargepower source 108 relative to the power applied by radio frequency powersource 103. Typical discharge power for weak plasma can be several wattsto tens of watts, and the plasma density is between 10⁷-10⁸/cm³. Examplematerials for the monomer containing acrylate, such as ethoxylatedtrimethylolpropane triacrylate, or perfluorocyclohexyl methyl acrylate.

Metal Grid

Under general vacuum conditions, a pressure gradient may exist along theway from the gas inlet to the exhaust exit, even if no mesh exists. Thiscan be measured by vacuum meters at different positions of the vacuumchamber 101. Therefore, the strategic placement of the metal grid 105,such as introduced here, can increase the pressure difference betweendischarge cavity 104 and vacuum chamber 101 by hindering the carrier gasflow. Generally speaking, the pressure difference may increase with thenumber of layers, the mesh number, and transmissivity of the grid. Insome embodiments, each layer may have different characteristics. Forexample, one layer may have smaller openings while another layer haslarger openings. Additionally, there may be a preferred order for thegates (e.g., the carrier gas-based plasma moves through a gate withlarger openings before moving through a gate with smaller openings).

In some embodiments, the number of layers of metal grid 105 can rangefrom 2 to 6. Metal grid 105 can be made of materials including, forexample, stainless steel or nickel. Metal grid 105 ranges from 100 to1,000 mesh, and the transmissivity can range from 25% to 40%. Metal grid105 increases the pressure differential to reduce or to prevent backflowof carrier gas from vacuum chamber 101 to discharge cavity 104. In someembodiments, at least two layers of metal grid 105 are provided at theconnecting positions of the discharge cavities and the inner walls ofvacuum chamber 101. Metal grid 105 may be insulated from the inner wallof vacuum chamber 101.

In certain embodiments, metal grid 105 may be arranged at the connectingpositions of the discharge cavities and the inner walls of vacuumchamber 101. In some embodiments, at least two discharge cavities 104are provided on an outer wall of the vacuum chamber 101 in a sealedmanner. In some examples, the porous electrode 102 and the dischargecavities are able to discharge together or separately according to theneeds of the specific processes.

In one or more embodiments, a pulse power source 106 is coupled to themetal grid 105. The pulse power source 106 can be configured to providea positive electrical charge to the metal grid 105 in pulses, whereinplasma in the discharge cavity is blocked from entering vacuum chamber101 during a pulse-off period. The plasma in the discharge cavity can bepassed through to vacuum chamber 101 during a pulse-on period.

As a result, when power is applied, the plasma generated in dischargecavity 104 is released into vacuum chamber 101. For example, the plasmais blocked (at least partially) by metal grid 105 within dischargecavity 104 during a period of pulse-off (i.e., when no power is appliedto metal grid 105), and the plasma can pass through metal grid 105during a period of pulse-on (i.e., when power is applied to metal grid105) into vacuum chamber 101. In some embodiments, pulse power source106 outputs a positive pulse with the following parameters: peak is from20 to 140 V, pulse width is from 2 μs to 1 ms, and repeat frequency isfrom 20 Hz to 10 kHz.

Similarly, the metal grid 105 can place a hindering effect on thereverse-diffusion of the monomer vapor from the vacuum chamber 101 todischarge cavity 104. Moreover, since the pressure in the dischargecavity 104 can be higher than that in the vacuum chamber 101, themonomer vapor may not easily move from the vacuum chamber 101 to thedischarge cavity 104 through reverse-diffusion, thereby preventing themonomer vapor from being excessively decomposed and destructed by thecontinuously discharged plasma in the discharge cavity 104. In someembodiments, the metal grid 105 can help create a pressure differential,so as to reduce or to prevent the carrier gas from backflowing.

Monomer Vapor Pipe

Monomer vapor pipe 110 can be connected to vacuum chamber 101, and anoutlet can be located adjacent to discharge cavity 104. The other end ofmonomer vapor pipe 110 is connected to a monomer vapor source. In someembodiments, distance between the outlet of monomer vapor pipe 110 anddischarge cavity 104 can range from 1 to 10 cm. In one embodiment, themonomer vapor pipe 110 is directly connected to vacuum chamber 101rather than within discharge cavity 104. This is to avoid the monomervapor from being exposed to strong electrical charges from the dischargecavity 104.

In some embodiments, no monomer vapor is introduced into vacuum chamber101 when porous electrode 102 is activated during the pre-treatmentperiod (e.g., step 306). During the plasma polymerization coatingperiod, the monomer vapor may be partly discharged in and out ofdischarge cavity 104. However, discharge of monomer vapor into dischargecavity 104 may be undesirable because it may lead to excess breakdown ofthe monomer molecules. Thus, the monomer vapor pipe 110 may be designedto be directly connected to vacuum chamber 101 to avoid the monomervapor from being strongly discharged in discharge cavity 104 whenpassing through it. Rather, the carrier gas-based plasma isintermittently released from the discharge cavities to activate themonomer vapor with minimized discharge of it.

Tail Gas Collecting Tube and Vacuum Pump

Vacuum chamber 101 of the plasma polymerization coating apparatus 100may include a tail gas collecting tube 111 positioned vertically alongthe central axis of vacuum chamber 101. In some embodiments, vacuumchamber 101 is operable to have an air pressure lower than vacuumchamber 101 to collect excess reactive species in the atmosphere ofvacuum chamber 101 at a controlled exhaust rate.

One or more ends of the tail gas collecting tube 111 may be hollow andconnected to vacuum pump 116 at a gas exhaust port. Additionally, holesare distributed along the wall of tail gas collecting tube 111.Atmosphere in vacuum chamber 101 enters the tail gas collecting tube 111via the holes on the tail gas collecting tube 111 and is then dischargedfrom vacuum chamber 101 by vacuum pump 116. The power applied to vacuumpump 116 may range between 3-50 kW, and the pump rate may range between600-1200 m³/h. The inner diameter of tail gas collecting tube 111 mayrange from 25 to 100 mm. In some embodiments, holes can be evenlyprovided on the wall of tail gas collecting tube 111. The hole size mayrange from 2 to 30 mm, and the space between holes may range from 2 to100 mm.

The vacuum pump 116 may be configured to evaluate the atmosphere fromvacuum chamber 101 via tail gas collecting tube 111. The operation ofthe vacuum pump 116 may be controlled by receiving control signals fromcontroller 117 that indicate the pump rate at which the atmosphere ofvacuum chamber 101 is evacuated.

Vacuum pump 116 may receive control signals that initiate the operationof vacuum pump 116 to evacuate the atmosphere in vacuum chamber 101.This may be performed prior to the discharge of carrier gas or monomervapor in order to remove any undesired gases, plasma, reactive species,or contaminants before applying the plasma polymerization coating todevice 115. For example, when there is an excessively high concentrationof reactive species in vacuum chamber 101, control signals may bereceived from controller 117 indicating that the vacuum pump 116 shouldoperate at a maximum pump rate (e.g., 1200 m³/h). In contrast, whenthere is a lower concentration of reactive species, a minimum pump rate(e.g., 600 m³/h) may be used or operation of vacuum pump 116 may behalted.

Additionally, vacuum pump 116 may receive control signals that controlthe pump rate used to evacuate the atmosphere in vacuum chamber 101during the plasma polymerization coating process. In some examples, thegeneration of reactive species may result in varying concentrations ofreactive species at local regions within vacuum chamber 101.

In one example, the concentration of reactive species may be affected bythe amount or rate in which monomer vapor is introduced into vacuumchamber 101. If the monomer vapor is rapidly introduced, an excessiveamount of reactive species may form within vacuum chamber 101. Inaddition to the overall amount of reactive species, a high localconcentration of reactive species may form in a region where moremonomer vapor is introduced.

In another example. the generation of reactive species may be affectedby the rate and/or level of power of electrical discharge applied tocarrier gas. The greater rate or higher the power, the greater theamount of plasma may be generated overall. Additionally, the opening ofthe discharge cavity 104 where the electrical discharge is applied tocarrier gas may hold a greater local concentration of plasma. As theplasma converges with monomer vapors, the greater local concentration ofplasma may in turn result in a greater local concentration of reactivespecies.

In yet another example, the generation of reactive species may beaffected by the rate in which energy is transferred from the plasma tothe monomer vapor. For example, the local concentration within vacuumchamber 101 where the plasma and monomer vapor meet may increase if therate in which energy is transferred from the plasma to the monomer vaporis high. Additionally, the local concentration of reactive species mayincrease in a region where there is an ideal amount of plasma andmonomer that converge.

For another example, the concentration of reactive species may beaffected by the deposition of reactive species on device 115. As thereactive species are deposited on device 115, less reactive speciesremains in the atmosphere of vacuum chamber 101. Therefore, as reactivespecies moves from the outer regions of vacuum chamber 101 towards thecentral axis and gets deposited on device 115, a gradient may form wherethe concentration of reactive species in the atmosphere decreasestowards the central axis of vacuum chamber 101. In an example of acountervailing effect, the concentration of reactive species in theatmosphere increases as the reactive species converges towards thecentral axis of vacuum chamber 101. A person of ordinary skill in theart will recognize that various other factors may affect theconcentration of reactive species in vacuum chamber 101. For example,the concentration of reactive species may be affected by the ratio ofplasma to monomer vapors.

Based upon the various factors affecting the generation of reactivespecies described above, an uneven or undesired level of concentrationof reactive species may form within vacuum chamber 101. In someembodiments, the pump rate of vacuum pump 116 may be controlled tocompensate for the uneven or undesired level of concentration ofreactive species. Vacuum pump 116 may receive control signals toincrease the pump rate to decrease the overall amount of reactivespecies within vacuum chamber 101. Additionally, vacuum pump 116 mayreceive control signals to reduce a greater concentration of reactivespecies at a local region such as where the plasma and monomer vaporconverges.

For example, the pump rate may be increased to eliminate an increase inthe local concentration of reactive species where the plasma and monomervapor converges. In another example, the pump rate may be reduced toeliminate a reduced local concentration of reactive species where theelectrical power applied to carrier gas is lowered. A person of ordinaryskill in the art will recognize that the vacuum pump 116 may beconfigured in various ways to enhance the uniformity of reactive speciesin vacuum chamber 101. For example, the timing, periodic operation, andgradual increase/decrease of pump rates may be controlled to compensatefor changes in the concentration of reactive species or to compensatefor local regions with varying reactive species concentrations.

Hollow Guide Sleeve

In some embodiments, one end of the tail gas collecting tube 111 may beconnected to hollow guide sleeve 119. The hollow guide sleeve 119 may beconfigured as a support structure that allows tail gas collecting tube111 to rotate along the central axis of vacuum chamber 101. In someexamples, the tail gas collecting tube 111 may be inserted into thehollow guide sleeve. This may be accomplished by configuring the innerdiameter of the hollow guide sleeve 119 to be equal or larger than theouter diameter of tail gas collecting tube 111. A person of ordinaryskill in the art would recognize that the hollow guide sleeve 119 may beconfigured in other ways to function as a support structure. Forexample, hollow guide sleeve 119 may be configured to be inserted intotail gas collecting tube 111. This may be accomplished by configuringthe outer diameter of the hollow guide sleeve 119 to be equal or smallerthan the inner diameter of tail gas collecting tube 111.

Rotation Rack

Vacuum chamber 101 of the plasma polymerization coating apparatus 100may include rotation rack 112 operably coupled to a planetary rotationshafts 113 and configured to rotate along a central axis. In someembodiments, the primary rotation rack includes one or more rack layers,each rack layer holding a plurality of substrate platforms from the oneor more substrate platforms. In some embodiments, the primary rotationshaft may be coupled or otherwise integrated with tail gas collectingtube 111.

In some embodiments, rotation rack 112 is coupled to one or moreplanetary rotation shafts 113 that is in turn coupled to rotationplatforms 114. The planetary rotation shafts 113 may support planetaryrotation platforms 114 that rotate along a secondary axis which iscoaxial with planetary rotation shafts 113. Additionally, the planetaryrotation shafts 113 may be distal to the central axis of vacuum chamber101. The rotation of the primary rotation rack along the central axisand the rotation of the secondary rotation rack along the secondary axiscan provide the same rate of spatial movement for each of the one ormore substrates during the coating process in order to achieve uniformcoating. In some examples, the number of the planetary rotation shafts113 may be between 2 to 8, and the number of the planetary rotationplatforms 114 may be between 1 to 10.

Vacuum chamber 101 of the plasma polymerization coating apparatus alsoincludes one or more substrate platforms configured to carry the one ormore substrates that are to receive the plasma polymerization coating.Each substrate platform can be located on the secondary rotation rack.The substrate platforms may be planetary rotation platforms 114.Planetary rotation platforms 114 allow for placement of device 115 to betreated such that the device 115 is in continuous movement along vacuumchamber 101. The planetary rotation platforms 114 are secured alongplanetary rotation shafts 113, wherein each planetary rotation platforms114 rotates around their own planetary rotation axes while the planetaryrotation axes rotate around the central axis of vacuum chamber 101. Thecontinuous movement allows for uniform plasma polymerization treatmenton the surface of device 115.

Note that, even though there is no particular directional requirementfor the rotation of planetary rotation shafts 113 versus the rotation ofrotation rack 112, overall the rotations should be suitably tuned andadjusted (e.g., for the sake of rotational balance and stability) suchthat substantially all samples can experience the same spatial movementduring the coating process in order to achieve uniform coating.Similarly, there is no particular limitation on the rotational speed;however, it is apparent that an overly fast rotational speed isunfavorable because of the unnecessary power consumption, part wear, aswell as instability of the platform.

Polymerization Controller

In some embodiments, plasma polymerization coating apparatus 100includes controller 117 configured to provide control signals theregulate the operation of the various components of plasmapolymerization coating apparatus 100. The control signals allow theapparatus to regulate the plasma polymerization process applied todevice 115.

Controller 117 may transmit a rotation rate signal to rotary motor 118.The rotation rate signal indicates the rotational speed that rotarymotor 118 should operate. Regulating the rotational speed may determinethe rate that device 115 traverse vacuum chamber 101. For example, afaster rotational speed may allow the substrate to traverse vacuumchamber 101 relatively quickly. Therefore, any imbalance of theconcentration of plasma in the vacuum chamber 101 would be negatedbecause device 115 would be rapidly exposed to both ends of the plasmaconcentration gradient.

In some embodiments, the dispersal mechanism is communicatively coupledto the controller 117 to receive dispersal control signals from thecontroller to control the dispersal rate of the reactive species in asubstantially even manner on the one or more substrates. The dispersalcontrol signal controls the dispersal rate of the reactive species byregulating the applied electrical power to the dispersal mechanismand/or by regulating the rate of gas that enters the dispersal mechanismfor polymerization. In some embodiments, the dispersal rate controlsignal adjusts the dispersal rate to account for the density decrease inthe reactive species within vacuum chamber 101 resulting from thedeposition of the reactive species on to the one or more substrates andthe density increase within the reactive species in vacuum chamber 101resulting from the reactive species converging toward the center of thechamber such that the density of reactive species across vacuum chamber101 is uniform.

For example, controller 117 may transmit a dispersal control signal todischarge power source 108 to indicate the power that should be appliedto discharge source 107. Regulating the power applied to dischargesource 107 allows for control of the rate in which plasma is generatedin discharge cavity 104. Therefore, a change in the power to dischargesource 107 may affect a change in the density of plasma as well as theproperties of the plasma in vacuum chamber 101 and ultimately thethickness of the plasma applied to device 115.

In some embodiments, the pulse power source receives a pulse controlsignal from the controller, the pulse control signal regulating thepower and frequency of the positive electrical charge. Specifically,controller 117 may transmit a pulse control signal to pulse power source106. The pulse control signal indicates the power to be applied by pulsepower source 106 to metal grid 105. Specifically, pulse power source 106applies a positive electrical pulse bias on metal grid 105, thusallowing the plasma generated in discharge cavity 104 to beintermittently released into vacuum chamber 101. For example, metal grid105 may block the plasma within the discharge cavity 104 during a periodof pulse-off, and metal grid 105 may allow plasma to pass into vacuumchamber 101 during a period of pulse-on. Using this mechanism, the pulsecontrol signal controls the duration and frequency in which plasma isallowed to enter from discharge cavity 104 to vacuum chamber 101.

Controller 117 may transmit a radio frequency power control signal toradio frequency power source 103. The radio frequency power signalindicates to radio frequency power source 103 when to apply power toporous electrode 102 to generate plasma for removing impurities fromdevice 115. For example, controller 117 may transmit a radio frequencypower control signal to power on radio frequency power source 103 at thestart of a plasma polymerization process to pre-treat device 115 orafter the plasma has been applied to the substrate for post-treatment ofdevice 115 and vacuum chamber 101.

Controller 117 also transmits various control signals for regulating theintroduction and evacuation of gases into the planetary rotary rackdevice. For example, controller 117 transmits a carrier gas controlsignal to carrier gas pipe 109. This control signal indicates the ratein which carrier gases should be introduced into discharge cavity 104.Controller 117 also transmits a monomer vapor control signal to monomervapor pipe 110. The monomer vapor control signal indicates the rate inwhich monomer vapor gases are introduced into vacuum chamber 101.

In some embodiments, a collecting tube is communicatively coupled thecontroller to receive an exhaust rate control signal from the controllerto control the exhaust rate of the reactive species. For example,controller 117 provides a tail gas control signal to tail gas collectingtube 111. This signal controls the rate in which the atmosphere isevacuated from vacuum chamber 101. In some embodiments, the controllertransmits the exhaust rate control signal to adjust the rate thereactive species is exhausted from vacuum chamber 101. The exhaust rateis controlled to account for two factors contributing to the density ofthe reactive species within vacuum chamber 101: (1) the density decreasein the reactive species within vacuum chamber 101 resulting from thedeposition of the reactive species on to the one or more substrates and(2) the density increase in the reactive species in vacuum chamber 101resulting from the reactive species converging toward the center of thechamber such that the density of reactive species across vacuum chamber101 is uniform, (3) the increase in reactive species within vacuumchamber 101 based on the rate in which monomer vapor is introduced intothe reaction chamber, (4) the increase in reactive species within vacuumchamber 101 based on the rate in which electrical power is applied tocarrier gas to generate plasma, and (5) the increase in reactive specieswithin vacuum chamber 101 based on the rate in which energy from theplasma is transferred to the monomer vapor.

Controller 117 may be microcontrollers, general-purpose processors, ormay be application-specific integrated circuitry that providesarithmetic and control functions to implement the techniques disclosedherein. The processor(s) may include a cache memory (not shown forsimplicity) as well as other memories (e.g., a main memory, and/ornon-volatile memory such as a hard-disk drive or solid-state drive. Insome examples, cache memory is implemented using SRAM, main memory isimplemented using DRAM, and non-volatile memory is implemented usingFlash memory or one or more magnetic disk drives. According to someembodiments, the memories may include one or more memory chips ormodules, and the processor(s) on Controller 117 may execute a pluralityof instructions or program codes that are stored in its memory.

Rotary Motor

In some embodiments, plasma polymerization coating apparatus 100includes rotary motor 118 to rotate device 115 within vacuum chamber101. The rotation of device 115 enhances the uniformity of the appliedplasma polymerization coating on device 115. In some embodiments, rotarymotor 118 actuates the rotation of rotation rack 112 coupled to tail gascollecting tube 111 such that planetary rotation platforms 114 rotatealong a concentric path relative to the central axis of vacuum chamber101. Additionally, rotary motor 118 may actuate the rotation of thesubstrate platforms along the planetary rotation axes along planetaryrotation shafts 113. As noted above, control signals from controller 117may be used to control the rate that rotary motor 118 operates to rotaterotation rack 112 and/or planetary rotation shafts 113. In someexamples, the rotational frequency may range from 10 Hz to 50 Hz.Additionally, in some embodiments, the rotational frequency may beadjusted dynamically during the plasma polymerization coating process(e.g., process 300).

Rotary motor 118 may be located in various locations relative to vacuumchamber 101. For example, rotary motor 118 may be located below vacuumchamber 101 and coupled to the lower end of tail gas collecting tube111. In other examples, rotary motor 118 may be located at the center ofvacuum chamber 101 and coupled to the middle of tail gas collecting tube111. In yet other examples, rotary motor 118 may be located above vacuumchamber 101 and coupled to the upper end of tail gas collecting tube111. Additionally, rotary motor 118 may be located within vacuum chamber101 or outside of vacuum chamber 101.

FIG. 2 is a schematic top view of the structure of plasma polymerizationcoating apparatus 100 shown in FIG. 1, according to one or moreembodiments of the present disclosure.

Overall, the present disclosure has various beneficial effects. First,the apparatus employs a central axis symmetrical vacuum chamber 101structure to maintain the uniformity of space polymerization reactivematerial density. The vacuum chamber 101 adopts a mechanism in which thegas is fed via the side wall, transported radially, and discharged alongthe direction of central axis.

In one or more embodiments, the carrier gas pipe 109 is provided in eachdischarge cavity 104 and with an outlet. A carrier gas can enter thedischarge cavities via carrier gas pipe 109, and then diffuse into thevacuum chamber 101 via the multilayer metal grid 105. The monomer vaporpipe 110 is provided with an outlet in front of discharge cavity 104 inthe vacuum chamber 101. A monomer vapor gas enters the vacuum chamber101 via monomer vapor pipe 110. In addition, a tail gas collecting tube111 is coaxially provided the vacuum chamber 101 along the axis of thevacuum chamber 101. The tail gas collecting tube vertically penetratesthrough the vacuum chamber 101. One end of the tail gas collecting tube111 is connected to vacuum pump 116, and holes are evenly distributed onthe wall of the tube. A tail gas enters the tail gas collecting tube viathe holes on the tail gas collecting tube, and then is discharged fromthe vacuum chamber 101 by vacuum pump 116.

In the foregoing approach, in which the gas is fed via the side wall,transported radially, and discharged along the direction of centralaxis, the gas transport process takes place in a convergent manner,which can facilitate an increased stability of reactive speciesconcentration in the space polymerization reaction, and a more evenlydistribution of reactive species. In one embodiment, the process startsby generating polymerization reaction reactive species when the monomervapor comes into contact with the carrier gas-based plasma in thevicinity of discharge cavity 104. Activated by the carrier gas, thegenerated polymerization reactive species are radially dispersed towardsthe axis of the vacuum chamber 101. As device 115 is rotated withinvacuum chamber 101, the amount of the polymerization reaction reactivespecies gradually decreases due to continuous consumption.Simultaneously, the polymerization reaction reactive species alsogradually converge, which can compensate for the foregoing decrease inthe amount of the polymerization reaction reactive species. In this way,the concentration of the polymerization reaction reactive species canremain stable. The bulk density of the reactive species in the vacuumchamber 101 can remain unchanged, and thus the batch treatment can enjoygood uniformity.

In other words, the reactive species discharge mechanisms and thecollecting tube can be collectively configured in a way such that, adensity decrease in the reactive species due to consumption of thereactive species can be substantially equal to a density increase in thereactive species due to the reactive species converging toward thecollecting tube. Therefore, the coordinated operation of the reactivespecifies discharge mechanism and tail gas collecting tube 111 canprovide uniform density of the reactive species across vacuum chamber101 and onto device 115. Specifically, in some implementations, adischarge rate of the discharge mechanism can be adjusted (e.g., viacontrolling the applied electrical power and/or an amount of gas)together with an exhaust rate of the collecting tube (e.g., viaadjusting the power of vacuum pump) such that a substantially uniformdensity of the reactive species across the vacuum chamber 101 can beachieved. In many embodiments, the aforesaid collective adjustment ofthe discharge mechanism and the collecting tube corresponds to the shapeof the cross section of the inner side wall of a given vacuum chamber101. That is to say, in these embodiments, the combination of thedischarge rate of the discharge mechanism and the exhaust rate of thecollecting tube is preferably tailored to match the particular shape(e.g., a circle, or a polygon) of the given vacuum chamber 101 so as toachieve the substantially uniform density of the reactive species.

As compared to conventional coating devices and technology, thedifference in substrate coating thickness of the same batch treatment inthe conventional coating devices can be greater than 30%, while thedifference in substrate coating thickness of the same batch treatmentusing the disclosed devices can be smaller than 10%.

Second, the apparatus also employs rotation rack 112 to significantlyimprove the uniformity of each substrate coating. In one or moreembodiments, the vacuum chamber 101 is provided with rotation rack 112.The planetary rotation platforms 114 on rotation rack 112 may performplanetary rotation movements in the vacuum chamber 101. In particular,the disclosed mechanism allows each planetary rotation platforms 114 torotate along planetary rotation axes (e.g., along planetary rotationshafts 113) while making a revolutionary movement in a concentric pathrelative to the central axis of the vacuum chamber 101 (e.g., along therotation of rotation rack 112 coupled to tail gas collecting tube 111).

Device 115 to be treated can be placed on a planetary rotation platforms114. The introduced planetary rotary movement allows the spatialposition and orientation of each substrate treated to changecontinuously during the process of the treatment, such that all of thespatial positions of different substrates in the process of coatingtreatment can be substantially the same, thereby eliminating thedifference in coating due to different spatial positions of differentsubstrates in the existing technology. Accordingly, the introducedtechniques may achieve the same coating effects and better uniformityfor substrates of different locations in the same batch.

Third, the apparatus is able to greatly increase the volume of thevacuum chamber 101, and significantly improve the treatment efficiency.Due to the improvements in the structures of vacuum chamber 101 androtation rack 112, coating film thickness uniformity can be greatlyimproved for the treatment in the same batch. In addition, the volume ofthe vacuum chamber 101 may be expanded by 5 to 6 times. Accordingly, thebatch treatment quantity and treatment efficiency have been greatlyincreased. In some embodiments, the apparatus according to the presentdisclosure can effectively protect the monomer vapor from beingdecomposed and destructed so as to obtain a high-quality polymercoating.

Plasma Polymerization Coating Process

One aspect of the techniques disclosed herein includes a reactivespecies discharge process. In one embodiment, the process begins bypositioning a substrate on a substrate platform located in a vacuumchamber. The atmosphere of vacuum chamber 101 is evacuated by a vacuumpump via an air exhaust port of a collecting tube positioned along acentral axis of vacuum chamber 101. The process proceeds by rotating, bya rotary motor, a primary rotation rack coupled to a primary rotationshaft. In some embodiments, the primary rotation rack is configured torotate along the central axis. Then, a carrier gas is discharged to adischarge cavity via an inlet valve. The carrier gas can facilitate areaction between the substrate and the reactive species. The processcontinues by discharging, monomer vapor into vacuum chamber 101 using afeeding port. The process creates, the reactive species by polymerizingthe monomer vapor in vacuum chamber 101 using carrier gas. The processthen deposits the reactive species onto the surface of the substrate toform a polymer coating.

FIG. 3 is a flowchart illustrating an exemplary reactive speciesdischarge process 300. In some embodiments, process 300 controls andcoordinates the various components of plasma polymerization coatingapparatus 100.

In step 301, device 115 is placed within vacuum chamber 101. In someembodiments, device 115 is placed on planetary rotation platforms 114 asdepicted in FIGS. 1 and 2. The placement of device 115 on planetaryrotation platforms 114 facilitates the movement of the device 115 acrossvacuum chamber 101 during the plasma polymerization coating process. Bytraveling around the different areas of the vacuum chamber 101, thenegative effects of plasma density variations are reduced or eliminatedto allow for a more even plasma coating on the substrate.

In step 302, vacuum pump 116 may evacuate the atmosphere within vacuumchamber 101. In some embodiments, controller 117 transmits controlsignals to vacuum pump 116 to control the evacuation of the atmospherewithin vacuum chamber 101. This process ensures that the atmosphere doesnot interfere with the plasma polymerization process and facilitatesplasma polymerization processes that require a vacuum. In some examples,vacuum pump 116 is coupled to tail gas collecting tube 111 to create anegative atmospheric pressure in tail gas collecting tube 111 relativeto the atmospheric pressure of vacuum chamber 101. The negativeatmospheric pressure creates a flow of gases out of vacuum chamber 101.Controller 117 may transmit control signals to vacuum pump 116 tocontrol the timing, power, and other operational parameters used forevacuating the atmosphere.

In step 303, rotation rack 112 rotates device 115 in vacuum chamber 101.In some embodiments, the controller may transmit control signals torotary motor 118 to control the rotation rate of the rotation rack 112to provide the same rate of spatial movement for each of the one or moresubstrates during the coating process in order to achieve uniformcoating. Specifically, controller 117 transmits control signals torotation rack 112 containing device 115 for plasma polymerizationcoating. Upon receiving the control signals, rotation rack 112 canrotate to cause the device 115 to rotate within vacuum chamber 101 inaccordance with various embodiments of the invention. In someembodiments, rotation rack 112 contains planetary rotation shafts 113and planetary rotation platforms 114 for holding device 115 undergoingthe plasma polymerization process. The rotary motor 118 generates therotation motion of rotation rack 112. Controller 117 may transmitcontrol signals to rotary motor 118 that control the timing, duration,and rate of the rotation.

In step 304, planetary rotation shafts 113 and planetary rotationplatforms 114 rotates device 115 in vacuum chamber 101. In someembodiments, the secondary rotation rack rotates on a secondary axisdifferent from the central axis. Specifically, controller 117 transmitscontrol signals to planetary rotation shafts 113. The control signalscause planetary rotation shafts 113 to independently rotate along asecondary axis in accordance with various embodiments of the invention.The additional rotation provides for a wider range of movement of device115 within vacuum chamber 101. This allows for additional mitigation ofnegative effects caused by plasma density variations by further changingthe position and orientation of each device 115 to be treated.

In step 305, carrier gas is introduced into discharge cavity 104. Insome embodiments, controller 117 transmits control signals to carriergas pipe 109 to cause it to introduce carrier gas into discharge cavity104 to activate the monomer vapor. When the carrier gas is introducedinto discharge cavity 104, an electrical charge is applied by dischargepower source 108 to discharge source 107. Due to the electrical charge,the carrier gas gets ionized in discharge cavity 104 and becomes plasma(i.e., a mixture of positive ions and electrons produced by ionization).In some embodiments, the carrier gas is continually introduced intodischarge cavity 104 and becomes plasma throughout the polymerizationprocess until step 309. Controller 117 may transmit control signals thatcontrol the timing and amount of carrier gas that is introduced intodischarge cavity 104 as well as the timing and power applied bydischarge power source 108 to discharge source 107.

In step 306, process 300 optionally generates a treatment plasma toremove impurities from the surface of the one or more device 115. Incertain embodiments, the treatment plasma may be introduced into vacuumchamber 101 prior to discharging the reactive species to vacuum chamber101. In other embodiments, the treatment plasma may also be generatedafter the reactive species is deposited on the surface of the substrate.

In some embodiments, the treatment plasma is generated by an electrodecoupled to a radio frequency power source. Specifically, controller 117transmits control signals to radio frequency power source 103 togenerate an electrical charge that generates plasma in vacuum chamber101. The plasma is generated to remove impurities from device 115undergoing plasma polymerization. Additionally, the plasma may activatethe surface of device 115 to allow binding between the surface of device115 and the plasma to form the plasma polymerization coating. In someembodiments, a carrier gas may be introduced from carrier gas pipe 109to propagate the plasma throughout vacuum chamber 101. Controller 117may transmit control signals that control the timing, power, and otheroperational parameters to radio frequency power source 103 to porouselectrode 102. In some examples, continuous flow of carrier gas mayoccur during this step.

In step 307, reactive species is generated for application to thesurface of device 115 undergoing plasma polymerization. A reactivespecies is generated when introducing plasma to monomer vapor. Energyfrom the plasma is transferred from the plasma to the monomer vapor toactivate the monomer vapor. In some embodiments, controller 117transmits control signals to monomer vapor pipe 110 to introduce monomervapor into vacuum chamber 101. Controller 117 also transmits controlsignals to discharge power source 108 to regulate the timing and amountof power to apply to discharge source 107. When power is applied fromdischarge power source 108 to discharge source 107, the carrier gas indischarge cavity 104 becomes plasma. This provides a mechanism tocontrol when the discharge cavity 104 produces the plasma.

Additionally, controller 117 may provide control signals to pulse powersource 106 to regulate the power applied to metal grid 105. Metal grid105 is coupled to pulse power source 106 and arranged at the connectingpositions of the discharge cavities and the inner walls of vacuumchamber 101. Metal grid 105 regulates the flow of the plasma generatedin step 305 that enters vacuum chamber 101 and the backflow of carriergas into discharge cavity 104. In some embodiments, controller 117 mayprovide control signals that control the timing and amount of carriergas that is introduced into discharge cavity 104.

Specifically, when power is applied to metal grid 105, plasma can passthrough metal grid 105, and when power is not applied to metal grid 105,plasma is blocked from passing through the metal grid 105. When theplasma travels through metal grid 105 into vacuum chamber 101, theplasma transfers energy to the monomer vapor to activate the monomervapor to a high-energy state (i.e., the monomer vapor become activatedspecies). In some embodiments, the carrier vapor may even cause somechemical bonds of the monomer to break and form reactive particles suchas free radicals. Also, in some examples, continuous flow of carrier gasmay occur during this step.

In step 308, the reactive species created in step 307 may be depositedto the surface of device 115 undergoing plasma polymerization.Specifically, the polymerization reaction reactive species is generatedfrom monomer vapor when the monomer vapor comes into contact with theplasma released in step 307 from discharge cavity 104. Activated by thecarrier gas plasma, the generated polymerization reactive species areradially dispersed towards the axis of the vacuum chamber 101 and ontodevice 115. In some embodiments, after the reactive species isintroduced to the vacuum chamber 101, the vacuum chamber 101 will have acombination of ionized species, free electrons, free radicals, excitedmolecules or atoms, and unchanged gas.

In step 309, reactive species discharge process 300 collects excessreactive species in the atmosphere of vacuum chamber 101 by reducing theair pressure at the collecting tube to be lower than the air pressure ofvacuum chamber 101. The exhaust rate of the vacuum pump is configured toaccount for: (1) the density decrease in the reactive species withinvacuum chamber 101 resulting from the deposition of the reactive specieson to the substrate, (2) the density increase in the reactive species invacuum chamber 101 resulting from the reactive species converging towardthe center of the chamber such that the density of the reactive speciesacross vacuum chamber 101 is uniform, (3) the increase in reactivespecies within vacuum chamber 101 based on the rate in which monomervapor is introduced into the reaction chamber, (4) the increase inreactive species within vacuum chamber 101 based on the rate in whichelectrical power is applied to carrier gas to generate plasma, and (5)the increase in reactive species within vacuum chamber 101 based on therate in which energy from the plasma is transferred to the monomervapor.

Specifically, controller 117 transmits control signals to vacuum pump116 to evacuate excess gas, plasma, and reactive species from theatmosphere of vacuum chamber 101. Vacuum pump 116 is coupled to tail gascollecting tube 111 to create a negative atmospheric pressure in tailgas collecting tube 111 relative to the atmospheric pressure of vacuumchamber 101. The negative atmospheric pressure creates a flow of gasesout of vacuum chamber 101.

In some embodiments, step 306 (i.e., the pre-treatment step) should belonger than one planetary rotation cycle, so that all the substratesamples have traveled to the closest point to the porous electrode toaccept plasma. For example, step 306 may require between 1-30 minutes.In comparison, step 308 is determined by the film thickness required. Ingeneral, step 308 should take longer than the other steps. For example,step 306 may require between 20-300 minutes. Finally, step 309 should beexecuted until excess monomers are exhausted from the chamber. Forexample, step 309 may require between 1-10 minutes.

Processing System

FIG. 4 is a block diagram illustrating an example of a processing system400 in which at least some operations described herein can beimplemented. For example, some components of the processing system 400may be implemented in a controller device (e.g., controller 117 of FIGS.1 and 2).

The processing system 400 may include one or more central processingunits (“processors”) 402, main memory 406, non-volatile memory 410,network adapter 412 (e.g., network interface), video display 418,input/output devices 420, control device 422 (e.g., keyboard andpointing devices), drive unit 424 including a storage medium 426, andsignal generation device 430 that are communicatively connected to a bus416. The bus 416 is illustrated as an abstraction that represents one ormore physical buses and/or point-to-point connections that are connectedby appropriate bridges, adapters, or controllers. The bus 416,therefore, can include a system bus, a Peripheral Component Interconnect(PCI) bus or PCI-Express bus, a HyperTransport or industry standardarchitecture (ISA) bus, a small computer system interface (SCSI) bus, auniversal serial bus (USB), IIC (I2C) bus, or an Institute of Electricaland Electronics Engineers (IEEE) standard 1394 bus (also referred to as“Firewire”).

The processing system 400 may share a similar computer processorarchitecture as that of a desktop computer, tablet computer, personaldigital assistant (PDA), mobile phone, game console, music player,wearable electronic device (e.g., a watch or fitness tracker),network-connected (“smart”) device (e.g., a television or home assistantdevice), virtual/augmented reality systems (e.g., a head-mounteddisplay), or another electronic device capable of executing a set ofinstructions (sequential or otherwise) that specify action(s) to betaken by the processing system 400.

While the main memory 406, non-volatile memory 410, and storage medium426 (also called a “machine-readable medium”) are shown to be a singlemedium, the term “machine-readable medium” and “storage medium” shouldbe taken to include a single medium or multiple media (e.g., acentralized/distributed database and/or associated caches and servers)that store one or more sets of instructions 428. The term“machine-readable medium” and “storage medium” shall also be taken toinclude any medium that is capable of storing, encoding, or carrying aset of instructions for execution by the processing system 400.

In general, the routines executed to implement the embodiments of thedisclosure may be implemented as part of an operating system or aspecific application, component, program, object, module, or sequence ofinstructions (collectively referred to as “computer programs”). Thecomputer programs typically comprise one or more instructions (e.g.,instructions 404, 408, 428) set at various times in various memory andstorage devices in a computing device. When read and executed by the oneor more processors 402, the instruction(s) cause the processing system400 to perform operations to execute elements involving the variousaspects of the disclosure.

Moreover, while embodiments have been described in the context of fullyfunctioning computing devices, those skilled in the art will appreciatethat the various embodiments are capable of being distributed as aprogram product in a variety of forms. The disclosure applies regardlessof the particular type of machine or computer-readable media used toactually effect the distribution.

Further examples of machine-readable storage media, machine-readablemedia, or computer-readable media include recordable-type media such asvolatile and non-volatile memory devices 410, floppy and other removabledisks, hard disk drives, optical disks (e.g., Compact Disk Read-OnlyMemory (CD-ROMS), Digital Versatile Disks (DVDs)), and transmission-typemedia such as digital and analog communication links.

The network adapter 412 enables the processing system 400 to mediatedata in a network 414 with an entity that is external to the processingsystem 400 through any communication protocol supported by theprocessing system 400 and the external entity. The network adapter 412can include a network adaptor card, a wireless network interface card, arouter, an access point, a wireless router, a switch, a multilayerswitch, a protocol converter, a gateway, a bridge, bridge router, a hub,a digital media receiver, and/or a repeater.

The network adapter 412 may include a firewall that governs and/ormanages permission to access/proxy data in a computer network and tracksvarying levels of trust between different machines and/or applications.The firewall can be any number of modules having any combination ofhardware and/or software components able to enforce a predetermined setof access rights between a particular set of machines and applications,machines and machines, and/or applications and applications (e.g., toregulate the flow of traffic and resource sharing between theseentities). The firewall may additionally manage and/or have access to anaccess control list that details permissions including the access andoperation rights of an object by an individual, a machine, and/or anapplication, and the circumstances under which the permission rightsstand.

FIG. 5 is a schematic front sectional view of example plasmapolymerization coating apparatus 100 with optional shafts and gears forrotating rotation rack 112 and/or planetary rotation shafts 113. In someembodiments, the polymerization coating apparatus 100 may include rotarymotor 118, motor shaft 120, motor shaft gear 121, tail gas collectingtube primary gear 122, tail gas collecting tube secondary gear 123,rotation rack shaft 125, rotation rack shaft primary gear 126, rotationrack shaft secondary gear 127, and planetary rotation shaft gear 128.

In some embodiments, rotary motor 118 is coupled to motor shaft 120,which may protrude from the housing of rotary motor 118. Additionally,motor shaft 120 may be coupled to motor shaft gear 121. Additionally,tail gas collecting tube 111 may be coupled to tail gas collecting tubeprimary gear 122 and tail gas collecting tube secondary gear 123.Similarly, rotation rack shaft 125 may be coupled to rotation rack shaftprimary gear 126 and rotation track shaft secondary gear 127.

In certain embodiments, the operation of rotary motor 118 rotates tailgas collecting tube 111. Specifically, motor shaft gear 121 may beengaged with tail gas collecting tube primary gear 122. When rotarymotor 118 rotates motor shaft 120, motor gear 121 drives tail gascollecting tube primary gear 122. As mentioned above, tail gascollecting tube 111 is coupled to, and therefore rotates with, tail gascollecting tube primary gear 122. In effect, the rotational motiongenerated by rotary motor 118 is transferred from motor shaft 120 totail gas collecting tube 111 via motor gear 121 and tail gas collectingtube primary gear 122.

In some embodiments, the rotational motion of tail gas collecting tube111 is transferred to rotation rack shaft 125. As mentioned above, tailgas collecting tube secondary gear 123 is coupled to, and thereforerotates with, tail gas collecting tube 111. Additionally, tail gascollecting tube secondary gear 123 is engaged with rotation rack shaftprimary gear 126. Therefore, when tail gas collecting tube 111 rotates,tail gas collecting tube secondary gear 123 also drives the rotation ofrotation rack shaft primary gear 126. Since rotation rack shaft primarygear 126 is coupled to rotation rack 125, the rotation of rotation rackshaft primary gear 126 drives the rotation of rotation rack 125. In someexamples, rotation rack shaft 125 may be enclosed within rotation rack112, implemented as a sleeve enclosing rotation rack 112, or otherwiseimplemented in any manner that transfers rotational motion from tail gascollecting tube 111 to planetary rotation shafts 113.

In various embodiments, the rotational motion of rotation rack shaft 125is transferred to planetary rotation shafts 113. As mentioned above,rotation rack shaft secondary gear 127 is coupled to, and thereforerotates with, rotation rack 125. Additionally, rotation rack secondarygear 127 is engaged with planetary rotation shaft gear 128. Therefore,when rotation rack 125 rotates, rotation rack secondary gear 127 alsodrives the rotation of planetary rotation shaft gear 128. Sinceplanetary rotation shaft gear 128 is coupled to planetary rotationshafts 113, the rotation of planetary rotation shaft gear 128 drives therotation of planetary rotation shafts 113.

One effect of the optional shafts and gears is that rotational motiongenerated by rotary motor 118 is transferred to tail gas collecting tube111 and/or planetary rotation shafts 113 at various controlledrotational rates. For example, a series of gears of various diametersmay be used to implement a gear ratio to achieve a desired torque orrotational rate. Additionally, the various gears may be engaged totransfer rotational motion between gears or disengaged to stop thetransfer of rotational motion between gears. Further, the series ofgears of various diameters may be contained in a gearbox. In anotherexample, the series of gears may be divided into groups (e.g., motorshaft gear 121 and tail gas collecting tube primary gear 122 in onegroup), and each group of gears may be contained within a gearboxhousing. Additionally, the one or more gearboxes may be communicativelycoupled the controller 117 for receiving control signals. For example,the control signals may indicate the size of the gears to select as wellas the gears to engage or disengage.

For example, the tail gas collecting tube 111 and/or planetary rotationshafts 113 may be rotated at a controlled rate by selecting specificsize ratios of the various gears. Specifically, the size ratio of motorshaft gear 121 and tail gas collecting tube primary gear 122 may beselected to ensure that tail gas rotation rack 112, and in turn rotationplatforms 114, rotate along a central axis of vacuum chamber 101 at acontrolled rate. Similarly, a size ratio of tail gas collecting tubesecondary gear 123 and rotation rack shaft 125 may be selected to ensurethat rotation rack shaft 125 rotates at yet another controlled rate.Finally, a size ratio of rotation rack shaft secondary gear 127 andplanetary rotation shaft gear 128 may be selected to ensure thatplanetary rotation shafts 113 rotates at a specific controlled rate.Therefore, the size ratios of tail gas collecting tube secondary gear123, rotation rack shaft 125, rotation rack shaft secondary gear 127,and planetary rotation shaft gear 128 may be selected to ensure thatplanetary rotation shafts 113, and in turn rotation platforms 114,rotate along a planetary axis of vacuum chamber 101 at a controlledrate.

The controlled rates may ensure that a plasma polymerization coating isuniformly applied to the one or more device 115. The controlled ratesmay be a rate that is fast enough so that each of the one or more device115 may traverse the various regions of vacuum chamber 101 that havevarying densities of monomer vapors, carrier gases, plasma, reactivespecies, etc. By ensuring that each of the one or more device 115traverses the various regions, each of the one or more substratesexperiences the same atmospheric variations and receive the same uniformplasma polymerization coating across each substrate. Additionally, thecontrolled rate may ensure that the orientation of each of the one ormore device 115 is shifted to ensure that the uniform plasmapolymerization coating is uniform across the surface of each individualsubstrate.

FIG. 6 is a flowchart illustrating an exemplary reactive speciesdischarge process 600. In some embodiments, process 600 may be performedby the various components of plasma polymerization coating apparatus100. Additionally, process 600 may be used to apply a plasmapolymerization coating to device 115.

In step 601, process 600 prepares vacuum chamber 101 for performingexemplary reactive species discharge process 600 to device 115. Theinitialization operation is performed to ensure that proper conditionsare met before the plasma polymerization coating is applied. In certainembodiments, step 601 may be performed in a manner that is consistentwith steps 301-305 of FIG. 3.

As part of the initiation operation, device 115 may be properlypositioned in vacuum chamber 101 for receiving the plasma polymerizationcoating. For example, device 115 may be placed on planetary rotationplatforms 114 as depicted in FIGS. 1 and 2. The placement of device 115on planetary rotation platforms 114 facilitates the movement of device115 across vacuum chamber 101 during the plasma polymerization coatingprocess to reduce the negative effects of plasma density variations andallow for a more uniform plasma coating on device 115.

In some embodiments, the atmospheric conditions of vacuum chamber 101are properly set to ensure that the atmosphere is suitable for theplasma polymerization process. For example, vacuum chamber 101 may beclosed so that vacuum pump 116 can evacuate the atmosphere in vacuumchamber 101 until the atmosphere reaches between 10 to 300 mTorr. Inaddition to pressure, the temperature of vacuum chamber 101 may beregulated to facilitate the plasma polymerization process. In someexamples, the temperature of vacuum chamber 101 may be controlled tofall between 30 to 60° C.

The device may be moved in a consistent manner during any period inprocess 600. For example, plasma polymerization coating apparatus 100may begin rotation of rotation rack 112 to rotate device 115 along thecentral axis of the vacuum chamber 101 at a controlled rotational rate.For example, rotation rack 112 may rotate device 115 along the centralaxis at a speed of between 1.5 to 2.5 rotations per minute.Additionally, plasma polymerization coating apparatus 100 may beginrotation of planetary rotation shafts 113 and planetary rotationplatforms 114 to rotate device 115 in vacuum chamber 101 along asecondary axis at a controlled rotational. In some embodiments, thesecondary rotation rack rotates on a secondary axis that is distal fromthe central axis of vacuum chamber 101.

Controller 117 may transmit control signals to rotary motor 116 andother components in plasma polymerization coating to device 115 tocontrol the timing and rotational rate of rotation racks 112 and/orplanetary rotation shafts 113. Additionally, the operation of rotationracks 112 and/or planetary rotation shafts 113 coincides with theapplication of electrical power to metal grid barrier 105 tosimultaneously move the electrical connector throughout vacuum chamber101 while depositing reactive species on the surface of device 115.

In some embodiments, the rotation of rotation racks 112 and/or planetaryrotation shafts 113 results in the movement of device 115 within vacuumchamber 101. The movement may include a linear reciprocating motion or acurvilinear motion relative to a central axis of the reaction chamber.Additionally, the curvilinear motion may include one or more of acircular motion along the central axis, an elliptical motion along thecentral axis, a spherical motion, and a curvilinear motion with otherirregular routes. Additionally, in some embodiments, the operation ofrotation racks 112 and/or planetary rotation shafts 113 varies theorientation of device 115 relative to the central axis of vacuum chamber101 during the deposition of the reactive species onto device 115.Additionally, the rotational rate of rotation racks 112 and planetaryrotation shafts 113 may be configured independently.

In certain embodiments, treatment plasma may be introduced into vacuumchamber 101 to remove impurities from the surface of device 115 andprevent defects in the plasma polymerization coating. Additionally, thetreatment plasma may activate the surface of device 115 to allow bindingbetween the surface of device 115 and the reactive species used to formthe plasma polymerization coating. The treatment plasma may be generatedby applying an electrical charge from radio frequency power source 103to porous electrode 102. In some embodiments, controller 117 maytransmit control signals that control the timing, power, and otheroperational parameters to radio frequency power source 103. For example,the treatment plasma may be applied prior to discharging the reactivespecies to vacuum chamber 101 and/or after the reactive species isdeposited on the surface of the substrate. In some examples, the powerof the electrical charge applied by radio frequency power source 103 maybe a continuous discharge, pulse electrical discharge, or a periodicalternating electrical discharge. Additionally, the power of theelectrical charge and the duration of the electrical charge may bealtered according to the desired plasma polymerization coating. In someexamples, the electrical power applied by radio frequency power source103 may be between 120-400 Watt and the duration of the electricalcharge may be between 60 to 450 seconds.

In step 602, plasma is generated from carrier gas introduced fromcarrier gas pipe 109 into discharge cavity 104. The plasma is generatedby applying an electrical discharge from discharge power source 108 todischarge source 107. In some embodiments, step 602 may be performed ina manner consistent with step 305 of FIG. 3. After the carrier gas isintroduced into discharge cavity 104, an electrical charge is applied bydischarge power source 108 to discharge source 107. The electricalcharge ionizes the carrier gas and causes the carrier to become plasma.Controller 117 may transmit control signals that control the timing andamount of carrier gas that is introduced into discharge cavity 104 aswell as the timing and power applied by discharge power source 108 todischarge source 107. In some embodiments, the carrier gas may includeone or more of: helium, neon, krypton, and argon. However, a person ofordinary skill in the art may recognize that other elements may be usedas the carrier gas based upon, for example, the ability to transferenergy to monomer vapors.

In certain embodiments, the electrical discharge may be generated usingone or more of: a radio frequency discharge, microwave discharge,intermediate frequency discharge, sine or bipolar pulse waveform, highfrequency discharge, and electric spark discharge. Additionally, thehigh frequency discharge and the intermediate frequency discharge mayhave a sine or bipolar pulse waveform. In some examples, the radiofrequency discharge produces plasma though a high frequencyelectromagnetic field discharge. In other examples, the high frequencydischarge and the intermediate frequency discharge have a sine orbipolar pulse waveform.

In yet another example, the microwave discharge uses microwave energy toexcite plasma. The microwave method has the advantage of having highenergy utilization efficiency. In addition, the microwave discharge doesnot use an electrode and the resulting plasma is pure. Therefore, themicrowave discharge provides high quality, high speed, and large areaapplication of the plasma polymerization coating.

In some embodiments, a pulse electrical discharge or a periodicalternating electrical discharge may be applied by discharge powersource 108 to generate plasma for release into vacuum chamber 101 duringspecific periods of process 600. In one example, a pulse electricaldischarge uses a power of between 50 to 200 Watts for a duration ofbetween 600 to 3,600 seconds. Additionally, the frequency of the pulseelectrical discharge may be between 1 to 1,000 HZ, and the duty cycle ofthe pulse may be between 1:1 to 1:500. In yet another example, theperiodic alternating electrical discharge uses a power of 50-200 Wattsfor a duration of between 600 to 3,600 seconds. Additionally, thealternating frequency of the discharge may be between 1 to 1,000 HZ. Insome embodiments, the periodic alternating electrical discharge may be asawtooth waveform, a sine waveform, a square waveform, a full-waverectifying waveform, or a half-wave rectifying waveform.

In step 603, a monomer vapor may be introduced into vacuum chamber 101.In some embodiments, step 603 may be performed in a manner consistentwith step 307 of FIG. 3. The monomer vapor is used to generate reactivespecies that are deposited on device 115 to form the plasmapolymerization coatings. Reactive species may be released from themonomer vapors when is energy transferred from plasma to the monomervapor. In some embodiments, the monomer vapor may be partly dischargedinto discharge cavity 104 to be released into vacuum chamber 101. Inother embodiments, monomer vapor may be released via monomer vapor pipe110 directly into vacuum chamber 101 to avoid the monomer vapor frombeing discharged in discharge cavity 104. In yet other embodiments,controller 117 may transmit control signals to monomer vapor tail pipe110 to select the type of monomer vapor to release, the rate the monomervapor is released, and the timing in which the monomer vapor isreleased. In some embodiments, the monomer vapor is introduced intovacuum chamber 101 at a rate such that the atmosphere reaches between 10to 300 mTorr.

Various monomer vapors may be selected to achieve a compact and uniformplasma polymerization coating with good electrical insulation propertiesand a low breakdown voltage. In some embodiments, the monomer vapors mayinclude one or more of: a first vapor comprising at least one organicmonomer with a low dipole moment, a second vapor comprising at least onepolyfunctional unsaturated hydrocarbon and hydrocarbon derivativemonomer, a third vapor comprising at least one monofunctionalunsaturated fluorocarbon resin monomer, and a fourth vapor comprising atleast one organosilicon monomer in a Si—Cl, Si—O—C, or ring structure.

The monomer vapor may include a first vapor comprising at least oneorganic monomer with a low dipole moment. The low dipole polymer with alow dipole moment may reduce the interference to electrical signalsacross the plasma polymerization coating. In certain embodiments, thefirst vapor may include one or more of: p-xylene, benzene, toluene,carbon tetrafluoride, α-methylstyrene, poly-p-dichlorotoluene,dimethylsiloxane, allylbenzene, decafluorobiphenyl,decafluorobenzophenone, perfluoro (allylbenzene), tetrafluoroethylene,hexafluoropropylene, 1H,1H-perfluorooctylamine, perfluorododecyl iodide,perfluorotributylamine, 1,8-diiodoperfluorooctane, perfluorohexyliodide, perfluorobutyl iodide, perfluorodecyl iodide, perfluorooctyliodide, 1,4-bis(2′,3′-epoxypropyl) perfluorobutane,dodecafluoro-2-methyl-2-pentene, 2-(perfluorobutyl) ethyl methylacrylate, 2-(perfluorooctyl) ethyl methyl acrylate,2-(perfluorooctyl)iodoethane, perfluorodecyl ethyl iodide,1,1,2,2-tetrahydro perfluorohexyl iodide, perfluorobutyl ethylene,1H,1H,2H-perfluoro-1-decene, 2,4,6-tris(perfluoroheptyl)-1,3,5-triazine,perfluorohexyl ethylene, 3-(perfluorooctyl)-1,2-epoxypropane,perfluorocycloether, perfluorododecyl ethylene, perfluorododecyl ethyliodide, dibromo-p-xylene, 1,1,4,4-tetraphenyl-1,3-butadiene, andpolydimethylsiloxane (with molecular weight of 500-50,000).

The monomer vapor may also include a second vapor comprising at leastone polyfunctional unsaturated hydrocarbon and hydrocarbon derivativemonomer. The polyfunctional unsaturated hydrocarbon and hydrocarbonderivative monomer has at least two reactive groups to allow for theformation of a cross-linked polymeric coating. In some embodiments, thesecond vapor may include one or more of: 1,3-butadiene, isoprene,1,4-pentadiene, trimethylolpropane ethoxylate triacrylate, tri(propyleneglycol) diacrylate, poly(ethylene glycol) diacrylate, 1,6-hexanedioldiacrylate, ethylene glycol diacrylate, diethylene glycol divinyl ether,and neopentyl glycol diacrylate.

The monomer vapor may further include a third vapor comprising at leastone monofunctional unsaturated fluorocarbon resin monomer. Themonofunctional unsaturated fluorocarbon resin monomer is advantageousbecause it allows for the formation of a waterproof polymeric coating.The third vapor may include one or more of: the monofunctionalunsaturated fluorocarbon resin comprises: 3-(perfluoro-5-methylhexyl)-2-hydroxy propyl methyl acrylate, 2-(perfluorodecyl) ethyl methylacrylate, 2-(perfluorohexyl) ethyl methyl acrylate, 2-(perfluorododecyl)ethyl acrylate, 2-perfluorooctyl ethyl acrylate,1H,1H,2H,2H-perfluorooctyl acrylate, 2-(perfluorobutyl) ethyl acrylate,(2H-perfluoropropyl)-2-acrylate, (perfluorocyclohexyl) methyl acrylate,3,3,3-trifluoro-1-propyne, 1-acetenyl-3,5-difluorobenzene, and4-acetenyl benzotrifluoride.

Finally, the monomer vapor may include a fourth vapor comprising atleast one organosilicon monomer in a Si—Cl, Si—O—C, or ring structurethat is allows for the formation of wear resistant coatings. In someembodiments, the fourth vapor may include one or more of:tetramethoxysilane, trimethoxy hydrogen siloxane, triethoxyoctylsilane,phenyltriethoxysilane, vinyl tris(2-methoxyethoxy)silane,triethylvinylsilane, hexaethyl cyclo trisiloxane,3-(methacryloyloxy)propyltrimethoxysilane, phenyltris (trimethylsiloxy)silane, diphenyl diethoxysilane, dodecyltrimethoxysilane,triethoxyoctylsilane, dimethoxysilane, and 3-chloropropyltrimethoxysilane.

The vapors that are used in step 603 depend on the coating that is beingformed. For example, cross-linked structure monomers generate reactivespecies that improve the strength and water resistance of the plasmapolymerization coating. In some embodiments, steps 603-605 are performedto apply a transition layer to the surface of device 115. The transitionlayer is an intermediate layer that forms between the surface of device115 and the surface layer of the plasma polymerization coating. In someembodiments, the transition layer may include the second vaporcomprising at least one polyfunctional unsaturated hydrocarbon andhydrocarbon derivative monomer and/or the fourth vapor comprising atleast one organosilicon monomer in a Si—Cl, Si—O—C. As described above,the two vapors provide allows for the formation of a cross-linkedpolymeric coating and a structure that provides water resistance.

Process parameters used in process 600 may be varied based upon variouscharacteristics of the monomer vapors and carrier gases. For example,the types of vapors or ratio of different vapors introduced in step 603may be selected based upon the molecular bond energy, bond length, anddifferences in vaporization temperatures of different monomer vapors.Additionally, the higher the vaporization temperature, the temperaturethat is applied to the monomer vapor needs to be higher. In yet otherembodiments, the rate at which the monomer vapors are discharged may bevaried to affect the rate in which reactive species are generated andthe resulting density of reactive species in vacuum chamber 101. In someexamples, the monomer vapors may be discharged into the vacuum chamberat a rate of between 10 to 10-1000 μL/min.

Additionally, the energy applied to the first, second monomer vapor,and/or a carrier gas may be selected according to differences inmolecular bond energy, bond length, and differences in vaporizationtemperatures of different monomers to generate a compact transitionlayer and surface layer that provides water resistance and a lowbreakdown voltage. As described above, energy from plasma is transferredto the monomer vapor to release reactive species that are deposited ondevice 115. The energy that is required depends on the monomer vaporthat is used. For example, sufficient energy is required to break themolecular bonds of the monomer vapor and release the reactive species.If a reagent has larger bond energy, the energy applied to the monomerneeds to be larger. Similarly, the shorter the bond length of themonomer, the greater the energy is required.

In step 604, reactive species are generated for application onto thesurface of device 115. Reactive species are generated when plasmagenerated in step 602 is released into vacuum chamber 101 from dischargecavity 104 and energy from the plasma is transferred to the monomervapors released in step 603. In some embodiments, step 604 may beperformed in a manner consistent with step 307 of FIG. 3.

In some embodiments, the release of plasma from discharge cavity 104into vacuum chamber 101 may be regulated by metal grid 105.Specifically, controller 117 may provide control signals to pulse powersource 106 to regulate the power applied to metal grid 105. When poweris applied to metal grid 105, plasma can pass through metal grid 105,and when power is not applied to metal grid 105, plasma is blocked frompassing through the metal grid 105. In some embodiments, the plasma maycause chemical bonds of the monomer to break and form reactive particlessuch as free radicals.

In some embodiments, the release of plasma may be controlled by using aconstant electrical discharge or a periodic electrical discharge tometal gate 105. For example, applying a constant electrical discharge tometal gate 105 allows plasma to constantly flow into vacuum chamber 101.In another example, applying a periodic electrical discharge to metalgate 105 allows plasma to periodically flow into vacuum chamber 101. Theperiodic electrical discharge may be a continuous electrical dischargeor a discontinuous electrical discharge such as a pulse electricaldischarge. A waveform is continuous if it forms an unbroken curve alonga domain (e.g., the time domain). In contrast, a waveform isdiscontinuous if there is a break along the curve along that domain.

In some embodiments, the release of plasma may be performed usingmultiple stages. For example, the release of plasma may be performedusing a stage that applies a constant electrical discharge to metal gate105. The constant electrical discharge allows plasma to be constantlyreleased from discharge cavity 104 into vacuum chamber 101. Anotherstage may be performed by applying a periodic electrical discharge tometal gate 105. The periodic electrical discharge may be a continuous ordiscontinuous electrical discharge. For example, a continuous electricaldischarge may take the form of a sine waveform. In another example, adiscontinuous electrical discharge may take the form of a sawtoothwaveform, a square waveform, a full-wave rectifying waveform, ahalf-wave rectifying waveform, or a pulse discharge. A person ofordinary skill in the art will recognize that one or more stages may beperformed using any combination of constant and periodic waveforms.

The periodic waveforms may be generated using a variety of techniques toaffect the periodic electrical discharge that is applied to metal gate105. In one embodiment, the amplitude and frequency of the waveform maybe adjusted. For example, by increasing the amplitude of the waveform, agreater amount of electrical discharge is periodically applied to metalgate 105 to allow for a greater flow of plasma from discharge cavity 104into vacuum chamber 101. In another example, increasing the frequency ofthe waveform causes the electrical discharge that is applied to metalgate 105 to alternate more quickly. This may result in the flow ofplasma through metal gate 105 into vacuum chamber 101 to change morerapidly (e.g., alternate between a high plasma flow and a low plasmaflow, or alternate between a plasma-on period and plasma-off period).

In yet another technique, composite waveforms may be formed by combininga number of other waveforms. In one embodiment, a square waveform may becombined with a sinusoidal waveform. The square waveform may be aperiodic waveform that alternates between a minimum value and a maximumvalue. For example, the minimum value may be zero to provide an “off”state when no electrical discharge is applied to metal gate 105. Thesinusoidal wave may be sine wave that has a higher frequency than thesquare wave. If the minimum value of the square wave is a negative valuewith an amplitude that is greater than the amplitude of the sine wave,then the combination of the two waves would still result in a periodic“off” state because the value of the composite wave remains less thanzero during the minimum value of the square wave. When the square wavealternates to its maximum value, the composite waveform will have asinusoidal waveform. In effect, the composite waveform alternatesbetween an “on” or “off” state based upon whether the square waveform isat its maximum or minimum value, respectively. During the “on” state,the waveform provides an output value that alternates based upon thesine waveform.

In another embodiment, a DC bias waveform may be combined with aperiodic waveform. The DC bias waveform may be used to configure themean amplitude of the resulting composite waveform. For example, apositive DC bias waveform will increase the value of a square waveform.If the DC bias waveform is high enough to bring the minimum value of thesquare wave above zero, then the square wave will never have a valueless than zero. Practically speaking, this means that an electricaldischarge is always applied to metal gate 105 where the electricaldischarge alternates between a higher electrical discharge and a lowerelectrical discharge.

Yet another technique for generating a waveform includes clipping anexisting wave. Clipping is performed to limit a waveform once it exceedsa specific value. For example, a minimum toggle threshold may designatethe minimum value of a waveform. When the waveform goes below thatminimum toggle threshold, the waveform is clipped at the value of thatthreshold. For example, the minimum toggle threshold may be zero suchthat when the waveform drops below zero, the waveform will simply remainat zero. A waveform clipped by the minimum toggle threshold of zero willapply no electrical discharge to metal gate 105 and result in aplasma-off period. Similarly, a maximum toggle threshold may designatethe maximum value of a waveform. When the waveform exceeds that maximumtoggle threshold, the waveform is clipped at the value of thatthreshold. A person of ordinary skill in the art will recognize thatvarious techniques may be combined to generate a waveform. For example,the composite waveform described above may be adjusted by a togglethreshold to limit the amplitude of the waveform.

A hybrid plasma polymerization process may be performed by utilizing themetal grid 105 to precisely control the pulse of plasma that flows intovacuum chamber 101. For example, a periodic electrical discharge asdescribed above may be used to perform the hybrid plasma polymerizationprocess. During the periodic electrical discharge, electrical dischargeis periodically applied to metal gate 105. A plasma-on period occurswhen electrical discharge is applied to metal gate 105. In contrast, aplasma-off period occurs when no electrical discharge is applied tometal gate 105.

In some embodiments, this hybrid process starts with a plasma-on period(i.e., when an electrical charge is applied to metal gate 105). Asplasma flows into vacuum chamber 101 and is deposited on the surface ofdevice 115 during the plasma-on period, a portion of the plasma polymerformation occurs by a fragmentation-polyrecombination process throughthe plasma-chemical activation of chemically polymerizable monomers suchas vinyl or acrylic monomers. Subsequently, during a plasma-off period(i.e., when an electrical charge is not applied to metal gate 105),plasma does not flow into vacuum chamber 101. During this period,radical chain propagation occurs on the surface of device 115. In someexamples, a greater portion of the plasma polymer formation isattributable to the radical chain propagation of the plasma-off periodcompared to the fragmentation-polyrecombination process of the plasma-onperiod. In some embodiments, alternating between the plasma-on period(i.e., fragmentation-polyrecombination process) and plasm-off period(i.e., radical chain propagation process) results in an alternatingmicrostructure of layers that dissipates energy from the layers.

Using the precise control of plasma release provided by metal grid 105,a plasma polymerization coating with varying thicknesses of plasma-onand plasma-off sublayers may be produced. Specifically, the gradualstructure may be produced by changing the thickness of each layer formedduring a plasma-on or plasma-off period. For example, the thickness ofeach layer may decrease with each new layer applied onto device 115.

In step 605, the reactive species generated in step 604 are deposited tothe surface of device 115 undergoing plasma polymerization. In someembodiments, step 605 may be performed in a manner consistent with step308 of FIG. 3. The generated reactive species of step 604 may beradially dispersed towards the axis of the vacuum chamber 101 and ontodevice 115. In some embodiments, after the reactive species isintroduced to the vacuum chamber 101, the vacuum chamber 101 will have acombination of ionized species, free electrons, free radicals, excitedmolecules or atoms, and unchanged gas. In some embodiments, freeradicals are polymerized on the surface of device 115 to form a polymercoating.

The reactive species are deposited on the surface of device 115 togenerate a compact and uniform plasma polymerization coating with goodelectrical insulation properties and a low breakdown voltage associatedwith the breakdown effect. Specifically, the breakdown effect is amechanism that allows electrical conductivity through the coating. Sincethe polymer film is very thin and textured with numerous nanometer sizedholes, a low voltage may provide electrically conductive channels when alow voltage is applied across the coating.

Consistent with various embodiments disclosed herein, the movement ofdevice 115 (e.g., the movement started in step 601) may operatethroughout process 600 to ensure that device 115 travels across thevacuum chamber 101 through different regions of the atmosphere to ensurea uniform application of the plasma polymerization coating.Additionally, the treatment plasma of step 601 may activate organicsubstrate of device 115 to form dangling bonds that facilitate coatingdeposition and enhance the binding force between the surface of device115 and the plasma polymerization coating. The plasma polymerizationcoating resulting from step 605 may be a transition layer. In someembodiments, the transition layer is deposited directly on the surfaceof device 115. A surface layer may be subsequently deposited on thesurface of the transition layer.

In step 606, monomer vapors are introduced into vacuum chamber 101. Insome embodiments, step 606 may be performed in a manner consistent withstep 603. The monomer vapor is used to generate reactive species thatare deposited on device 115 to form the plasma polymerization coating.Reactive species may be released from the monomer vapors when is energytransferred from plasma to the monomer vapor.

The vapors that are introduced into vacuum chamber 101 in step 606depend on the coating that is being formed. For example, cross-linkedstructure monomers generate reactive species that improve the strengthand water resistance of the plasma polymerization coating. In someembodiments, steps 606-608 are performed to apply a surface layer to thesurface of device 115. In some embodiments, the surface layer of theplasma polymerization coating is applied to the surface of thetransition layer applied in steps 603-605. The surface layer may includea first vapor comprising at least one organic monomer with a low dipolemoment and/or a third vapor comprising at least one monofunctionalunsaturated fluorocarbon resin monomer. As described above, the firstand third vapors allow for the formation of low dielectric constantcoating and the formation of a waterproof polymeric coating.

In step 607, reactive species are generated in vacuum chamber 101. Insome embodiments, step 607 may be performed in a manner consistent withstep 604. Reactive species are generated when plasma generated in step602 are released into vacuum chamber 101 from discharge cavity 104 andenergy from the plasma is transferred to the monomer vapors released instep 603.

In step 608, the reactive species generated in step 604 are deposited tothe surface of device 115 undergoing plasma polymerization. In someembodiments, step 608 may be performed in a manner consistent with step605. The plasma polymerization coating resulting from step 608 may be asurface layer. In some embodiments, the surface layer may be depositedon the surface of the transition layer (e.g., the transition layerapplied in steps 603-605).

FIG. 7 is a diagram that illustrates an example plasma polymerizationcoating 700 applied on device 115. The plasma polymerization coating mayinclude transition layer 701 and surface layer 702. The plasmapolymerization coating may also include transition layer 703, surfacelayer 704, transition layer 705, and/or surface layer 706. Transitionlayers 701, 703, and 705 may be produced in a manner consistent withsteps 603-605 of FIG. 6. Similarly, surface layers 702, 704, and 706 maybe produced in a manner consistent with steps 606-608 of FIG. 6.

In some embodiments, transition layer 701 may be deposited directly onthe surface of device 115. Subsequently, surface layer 702 may besubsequently deposited on the surface of transition layer 701.Similarly, transition layer 703 may be deposited on the surface ofsurface layer 702, surface layer 704 may be deposited on the surface oftransition layer 703, transition layer 705 may be deposited on thesurface of surface layer 704, and surface layer 706 may be deposited onthe surface of transition layer 705.

In some embodiments, the transition layers 701, 703, 705 and/or surfacelayers 702, 704, 706 each may include one or more of: carbon, fluorine,oxygen, silicon, and hydrogen atoms. In some examples, the plasmapolymerization coating may have a ratio of oxygen atoms to carbon atomsfrom between 1:3 to 1:20. To some extent, oxygen atoms are hydrophilicwhile carbon atoms are hydrophobic. Therefore, if the ratio of oxygenatoms to carbon atoms is too high, then the water resistance of thecoating is degraded.

In some embodiments, the transition layers 701, 703, 705 and surfacelayers 702, 704, 706 each may be formed using a hybrid plasmapolymerization process, such as the process described in step 604 ofFIG. 6. The hybrid process starts with the plasma-chemical activation ofchemically polymerizable monomers such as vinyl or acrylic monomersduring the plasma-on period (i.e., when an electrical charge is appliedto metal gate 105) to perform a fragmentation-polyrecombination process.Subsequently, during a plasma-off period (i.e., when an electricalcharge is not applied to metal gate 105), radical chain propagationoccurs on the surface of device 115. In some examples, a greater portionof the plasma polymer coating formation is attributable to the radicalchain propagation of the plasma-off period compared to thefragmentation-polyrecombination process of the plasma-on period. Forexample, only a small fraction of the plasma polymerization coating maybe produced using the fragmentation-polyrecombination process of theplasma-on period. In some embodiments, alternating between the radicalchain propagation and the fragmentation-polyrecombination processresults in an alternating arrangement of layers that dissipates energyfrom the plasma polymerization coating.

The foregoing description of various embodiments of the claimed subjectmatter has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit the claimedsubject matter to the precise forms disclosed. Many modifications andvariations will be apparent to one skilled in the art. Embodiments werechosen and described in order to best describe the principles of theinvention and its practical applications, thereby enabling those skilledin the relevant art to understand the claimed subject matter, thevarious embodiments, and the various modifications that are suited tothe particular uses contemplated.

Although the Detailed Description describes certain embodiments and thebest mode contemplated, the technology can be practiced in many ways nomatter how detailed the Detailed Description appears. Embodiments mayvary considerably in their implementation details, while still beingencompassed by the specification. Particular terminology used whendescribing certain features or aspects of various embodiments should notbe taken to imply that the terminology is being redefined herein to berestricted to any specific characteristics, features, or aspects of thetechnology with which that terminology is associated. In general, theterms used in the following claims should not be construed to limit thetechnology to the specific embodiments disclosed in the specification,unless those terms are explicitly defined herein. Accordingly, theactual scope of the technology encompasses not only the disclosedembodiments, but also all equivalent ways of practicing or implementingthe embodiments.

The language used in the specification has been principally selected forreadability and instructional purposes. It may not have been selected todelineate or circumscribe the subject matter. It is therefore intendedthat the scope of the technology be limited not by this DetailedDescription, but rather by any claims that issue on an application basedhereon. Accordingly, the disclosure of various embodiments is intendedto be illustrative, but not limiting, of the scope of the technology asset forth in the following claims.

What is claimed is:
 1. A method for protecting an electrical connectorfrom corrosive damage using a polymerization process to generate aplasma polymerization coating, the method comprising: consistentlymoving, during a select period of time, the electrical connector withina reaction chamber; during the select period of time: applying atransition layer to the electrical connector by: discharging a firstmonomer vapor into the reaction chamber, generating a first reactivespecies from the first monomer vapor by discharging a firstpolymerization plasma into the reaction chamber, and depositing thefirst reactive species to form the transition layer on a surface of theelectrical connector, the transition layer having a first ratio ofoxygen atoms to carbon atoms; applying a surface layer to the electricalconnector by: discharging a second monomer vapor into the reactionchamber, generating a second reactive species from the second monomervapor by discharging a second polymerization plasma into the reactionchamber, and depositing the second reactive species to form the surfacelayer on a surface of the transition layer, the surface layer having asecond ratio of oxygen atoms to carbon atoms that is less than the firstratio; wherein the first monomer vapor includes: a first vaporcomprising at least one polyfunctional unsaturated hydrocarbon andhydrocarbon derivative monomer; a second vapor comprising at least onemonofunctional unsaturated fluorocarbon resin monomer; and/or a thirdvapor comprising at least one organosilicon monomer in a Si—Cl, Si—O—C,or ring structure; wherein the second monomer vapor includes: a fourthvapor comprising at least one organic monomer with a low dipole moment;and/or a fifth vapor comprising at least one monofunctional unsaturatedfluorocarbon resin monomer; and controlling a ratio of the vapors basedon differences in molecular bond energy, bond length and differences invaporization temperatures of the monomer vapors.
 2. The method of claim1, wherein the first monomer vapor and/or second monomer vapor includescross-linked structure monomers that improve the strength and waterresistance of the transition layer and/or the surface layer.
 3. Themethod of claim 1, further comprising varying the energy applied to thefirst monomer vapor, second monomer vapor, and/or a carrier gasaccording to differences in molecular bond energy, bond length, anddifferences in vaporization temperatures of different monomers to causethe transition layer and surface layer to be water resistant andelectrically conductive.
 4. The method of claim 1, wherein the firstmonomer vapor and/or second monomer vapor are discharged into thereaction chamber at a rate of 10-1000 μL/min.
 5. The method of claim 1,wherein the first polymerization plasma and/or second polymerizationplasma are formed by applying an electrical charge to a carrier gas inthe reaction chamber, and wherein the first polymerization plasma and/orsecond polymerization plasma are deposited using pulse electricaldischarge or periodic alternating electrical discharge.
 6. The method ofclaim 5, wherein, during the application of the surface layer, aduration of the pulse electrical discharge is 600-3,600 seconds, a powerapplied is 1-600 Watts, a frequency of the pulse electrical discharge is1-1000 Hz, and a duty cycle of the pulse is from 1:1 to 1:500.
 7. Themethod of claim 5, wherein during the application of the surface layer,a duration of the periodic alternating electrical discharge is 600-3,600seconds, a power applied is 1-600 Watts, and an alternating frequency is1-1000 Hz.
 8. The method of claim 1, further comprising applying anelectrical charge to a carrier gas to generate the first polymerizationplasma and/or second polymerization plasma.
 9. The method of claim 8,wherein the carrier gas includes an inert gas of argon (Ar) atoms. 10.The method of claim 1, wherein the transition layer and/or the surfacelayer comprise one or more of: carbon, fluorine, oxygen, silicon, andhydrogen atoms.
 11. The method of claim 1, wherein the first ratio ofoxygen to carbon atoms of the transition layer is between 1:3 to 1:20.12. The method of claim 1, wherein the first reactive species and/orsecond reactive species are free radicals that are released from thefirst monomer vapor and/or second monomer vapor when energy istransferred from the first polymerization plasma and/or secondpolymerization plasma to the first monomer vapor and/or second monomervapor.
 13. The method of claim 12, wherein the free radicals arepolymerized on the surface of the electrical connector to form a polymercoating.
 14. The method of claim 1, wherein the electrical connector isa USB™ Type-C connector, a micro-USB™ connector, a Lighting connector,an HDMI™ connector, a flexible printed circuit (FPC) connector, aboard-to-board (BTB) connector, a probe connector, or a radio frequency(RF) coaxial connector.
 15. The method of claim 1, wherein the secondratio of oxygen to carbon atoms is greater than zero.
 16. The method ofclaim 1, wherein controlling the ratio of the vapors includes: using afirst ratio of the vapors for the first monomer vapor; and changing,while consistently moving the electrical connector within the reactionchamber, the first ratio of the vapors to a second ratio of the vaporsfor the second monomer vapor.